The present invention relates to a circuit configuration for operating a household appliance, having a switching power supply, by means of which a control unit can be at least indirectly supplied with current for controlling processes of the household appliance, and having a pushbutton, by means of which the switching power supply can be coupled to a supply grid. The invention further relates to a corresponding method.
Such circuit arrangements are already known from the prior art. In order to generate required low voltages, for example 12, 9, 5, 3.3 volts, these circuit configurations normally include a switching power supply, by means of which a line voltage from a supply grid is converted into the aforementioned DC supply voltage. As a general rule, such circuit configurations furthermore have a control unit which is coupled indirectly or directly to the switching power supply and enables the control of processes of the household appliance and the operation of the circuit configurations.
A method and a device for reducing the energy consumption in the case of an electrical appliance fed by a voltage converter are known from the publication DE 195 30 594 C1. In this situation, during operation of the appliance the voltage converter is connected on the primary side for only short periods of time to the supply grid or to another electrical supply. During these periods of time, in addition to providing the supply for a possibly required appliance function the voltage converter also enables the charging of a suitable energy store, whereby in the periods of time during which the voltage converter is disconnected from the power supply the function of the appliance is assured by drawing energy from the energy store. The voltage converter is automatically connected to the supply grid as soon as the energy supply in the energy store runs short in order to charge said energy store or if the appliance function otherwise requires it.
To be regarded as a disadvantage associated with this known method, or this device, is the fact that during the periods of time in which the voltage converter is disconnected from the power supply a self-sustaining behavior of the device in the event of an extended power outage is no longer assured, as a result of which only an inadequate principle of operation is made possible.